Workhead assembly and mounting therefor, in bevel gear making machines

ABSTRACT

In a bevel gear making machine, a workhead assembly mounts the work for rotation about a vertical or generally vertical axis and in a stable secure position, permitting multiple movements of the workhead for various purposes, as will be understood. The workhead assembly is mounted between and supported by two spaced and parallel upstanding side walls of the machine frame and includes a workhead, a swinging base, and a slidable base connected together so that the workhead assembly is slidable back and forth in a direction parallel to the side walls. The side walls, and the swinging base and workhead are pivotable about an axis extending between the side walls. The horizontal slidable motion of the workhead adapts it for movement between work loading and unloading and cutting positions, and the pivotal movement of the workhead enables the axis of rotation of the work spindle to be adjusted so as to be in a vertical or somewhat inclined from the vertical position during cutting operations.

United States Patent 2,509,660 5/1950 Wingren 2,857,819 2,913,962

Inventors Appl. No. Filed Patented Assignee WORKI-IEAD ASSEMBLY AND MOUNTING THEREFOR, IN BEVEL GEAR MAKING MACHINES 19 Claims, 19 Drawing Figs.

U.S. Cl 90/5, 90/1 Field of Search 90/5, 6, 9.4, 3, 1; 51/95 References Cited UNITED STATES PATENTS 10/1958 Wildhaber et al. 11/1959 Carlsen et al 3,192,831 7/1965 Hunkeler 90/5 3,269,270 8/1966 Fowler 90/5 3,288,031 III] 966 Krastel et a1 90/5 Primary Examiner-Gil Weidenfeld Attorneys-Cushman, Darby and Cushman and Morton A. w

Polster ABSTRACT: In a bevel gear making machine, a workhead assembly mounts the work for rotation about a vertical or generally vertical axis and in a stable secure position, permitting multiple movements of the workhead for various purposes, as will be understood. The workhead assembly is mounted between and supported by two spaced and parallel upstanding side walls of the machine frame and includes a workhead, a swinging base, and a slidable base connected together so that the workhead assembly is slidable back and forth in a direction parallel to the side walls. The side walls, and the swinging base and workhead are pivotable about an axis extending between the side walls. The horizontal slidable motion of the workhead adapts it for movement between work loading and unloading and cutting positions, and the pivotal movement of the workhead enables the axis of rotation of the work spindle to be adjusted so as to be in a vertical or somewhat inclined from the vertical position during cutting operations.

sum 03 OF 14 PATENTEU JAN 5197:

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INVENTOR5 fie/var If jzwm 4 54 i ATTORNEYS WORKHEAD ASSEMBLY AND MOUNTING THEREFOR, 1N BEVEL GEAR MAKING MACHINES BACKGROUND AND OBJECTS The present invention relates to gear making apparatus and particularly to machines for making bevel gears, such as spiral bevel and hypoid gears.

The present invention is part of anoverall, general development of the Gleason Works which includes several inventions besides that disclosed and claimed herein. This development includes other inventions in bevel gear making machines such as: a novel structural orientation of cradle, tool holder, workhead and associated supporting machine structures, and the combination of that structural orientation with a novel control arrangement for the generating geartrain; a novel cradle housing and cradle assembly; a novel helical motion mechanism; a novel ratio-change mechanism; novel control means for the generating train; novel means for conveying gears or gear blanks to the cutting stations and transferring them between cutting stations with novel means for automatic stock division in going from one station to the other; a novel control means for controlling the operation of the work loading and unloading and automatic stock division mechanisms; a novel chamfering means designed to remove burrs, etc. from the roughed gears; and other novel structures and techniques, all of which are being covered in a series of patent applications. These applications are: Ser. Nos. 764,212, 764,213, 764,214, 764,222, 764,217, 764,218, 764,219, 764,220, 764,215, 764,216, filed contemporaneously herewith, and the disclosures of which are all incorporated herein by reference.

While the present development relates especially to the production of bevel pinion gears for the automotive industry, such as spiral bevel and hypoid gears, it will be apparent to those skilled in the art that features of this development and of the present invention may be used for making other types of gears and for industries other than the automotive industry.

It is a primary general object of the present invention to provide bevel gear making apparatus with novel work holding structures-by themselves, and in combination with structural arrangements and orientation of other machine parts especially adaptable for high speed production either in a single cutting station or in a series of cutting stations arranged in a production line, for example, as disclosed in the copending application Ser. No. 764,212, filed contemporaneously herewith.

A further object of the present invention resides in the provision, in bevel gear making machines, of novel structures and combinations in a workhead assembly providing for improved holding of the work while allowing various controlled movement of the workhead, such as adjustment of the axis of rotation of the work, adjustment of the vertical position of the workhead, movement of the workhead between work loading and unloading and cutting positionsJA related object is to provide in such a workhead assembly and advantageous construction and arrangement of parts simplifying construction and assembly. A further related object is to provide in combination with such a workhead assembly an arrangement of clamping means for holding the various movable parts in secure operating position, once all of the desired adjusting movements thereof have been accomplished.

1n the illustrative embodiment of the invention, the workhead assembly is constructed so that the work spindle is arranged with its axis of rotation in a vertical or generally vertical position, depending on its adjustment, and the workhead assembly will be slidably connected to parallel, upstanding sidewall members so as to be reciprocable or slidable in a horizontal direction. It is contemplated that the cradle containing the cutting tool holder be arranged with the axis of cradle rotation disposed horizontally, as is conventional, and generally parallel to the sidewall members, and above the workhead assembly, as indicated in the copending application Ser. No. 764,212. It is further contemplated that the workhead assembly include a workhead, a swinging base, and a slidable base operatively connected to each other and to the upstanding sidewall members so that the various controlled movement of the workhead may be effected, and with clamping means being provided for holding the parts in their adjusted positions for a cutting operation, whereby the work may be conveniently and advantageously held in a firm, secure and stable position during cutting operations to resist and minimize vibrations, etc., and thereby minimize distortions or deviations of the desired cutting pattern. The novel workhead assembly will accordingly be well adapted to be utilized in connection with much higher speeds of operation of the cutting tool without sacrificing quality and precision in the final product, as will be understood. Thus, it is eminently suitable for use in the development referred to above and designed for more automated, high speed production of bevel pinion gears for the automotive industry, as discussed in the copending application Ser. No. 764,212.

In this connection, it will be noted that the horizontal movements of the workhead assembly, referred to above, are designed to be coordinated with a work loading and unloading arrangement, and a conveyor means, as disclosed in the copending application Ser. No. 764,219, referred to above, so as to provide a more automatic operation, especially in connection with a double roughing machine, or a double finishing machine, or a combination of a double roughing machine with a double finishing machine, as disclosed in the copending application Ser. No. 764,212, referred to above.

Further objects and advantages of the invention reside in the novel design and construction of various parts of the workhead assembly, referred to above, and the novel arrangement, interconnection, and orientation of these parts with each other and with associated structures in the machine so as to permit more efficient operation at high speeds while being relatively simple to construct and assemble.

Further objects and advantages of the invention will be in part obvious and in part pointed out hereinafter.

The novel features of the invention may best be made clear from the following description and accompanying drawings in which:

' FIG. 1 is a perspective view of a double gear cutting machine embodying the invention, and with some of the parts not shown for convenience of illustration;

FIG. 2 is a somewhat schematic, plan view, on a reduced scale, of a single gear cutting machine embodying certain features of the invention;

FIG. 3 is a somewhat schematic, plan view, on a reduced scale, of a double gear cutting machine embodying certain features of the invention;

FIG. 4 is a somewhat schematic, plan view, on a reduced scale, showing two double cutting machines embodying certain features of the invention;

FIG. 5 is an enlarged perspective view of a single machine embodying the invention;

FIG. 6 is an enlarged, fragmentary, perspective view of the sliding base of the workhead assembly, embodying the invention, and shown adjacent an upstanding sidewall means on the machine frame, and viewed looking to the right in FIG. 5;

FIG. 7 is a still further enlarged, fragmentary, perspective view of the other end of the workhead assembly, and showing an exemplary arrangement for connection thereof to the other upstanding sidewall means, and viewed in the direction from right to left in FIG. 5;

FIG. 8 is an enlarged, elevational, partially fragmentary view of an illustrative embodiment of the workhead assembly shown in H0. 5, with certain parts omitted for convenience of illustration, and viewed in the direction from left to right in FIG. 5; I

FIG. 9 is an enlarged, fragmentary, plan view, partially in horizontal section, of the left-hand end of the workhead assembly and sidewall means of FlG. 5;

FIG. 10 is an elevational view of the structure shown in H0. 9, on a reduced scale, partially in vertical section, and as viewed from right to left in FIG. 9;

FIG. 11 is an enlarged, and partially fragmentary, elevational view of an exemplary means for pivoting the workhead assembly, partially broken away and in section to illustrate certain parts thereof;

FIG. 12 is an elevational view of the structure shown in FIG. 11, viewed in the direction from right to left in that FIG, and partially vertically sectioned, and indicating exemplary connections, slidable base, and swinging base of the workhead assembly;

FIG. 13 is an enlarged, fragmentary and perspective view of an exemplary sidewall means to be associated with one end of the workhead assembly shown in FIG. 5, and viewed from the other side of the right-hand end of that FIG. and looking toward the left in FIG.

FIG. 14 is an enlarged, fragmentary, plan view of the structure shown in FIG. 13, and partially in section, indicating an exemplary arrangement for reciprocating the workhead assembly, horizontally or back and forth between work loading and unloading positions, as will be understood;

FIG. 15 is an enlarged, fragmentary, vertically sectioned view of an exemplary arrangement providing for swinging or pivoting of the swinging base of the workhead assembly relative to the slidable base, and including means for clamping the swinging base in adjusting position;

FIG. 16 is an enlarged diagrammatic view illustrating somewhat schematically the generating train and control means therefor,

FIG. 17 is a fragmentary plan view of the workhead;

FIG. 18 is a fragmentary plan view of the left-hand end of cylinder housing shown in FIGS. 13 and. 14; and

FIG. 19 is a vertical sectional view taken along line 19-19 of FIG. 18.

referring now to the drawings, a double gear cutting machine embodying the present invention is shown in FIG. 1. This machine is a double finishing machine, wherein each of the cutting stations does a finishing operation. However, it will be understood that a double roughing machine embodying the invention may have a similar external appearance and the same basic design with certain structural modifications adapting it for roughing, rather than finishing, as will be understood to those skilled in the art and as will be apparent from the series of applications being filed contemporaneously herewith. The double finishing machine is identified by numeral 20 and, a double roughing machine 22 is shown in FIG. 4 adjacent and at the side of the finishing machine 20. Each machine includes two cutting stations as indicated by reference characters 24a, 24b, 24 0, 24d and each machine comprises a frame 26a, 26b on which the cutting stations are presented.

A single machine 28 is shown in FIG. 2 and will now be described in some detail, it being understood that like reference numerals will be utilized to designate corresponding parts of the double roughing and finishing machines shown in FIG. 4. The single machine 28 can be built for use as a rougher for rough cutting of the work, or with somewhat different internal mechanisms, it can be built as a finisher capable of finishing a previously roughed gear blank. It may be built as shown for manual loading of the work, or equipped for automatic loading using an additional loader attachment (not shown).

FIG. 2.illustrates what is called the left side version and it includes the frame 26c, on which is mounted a cradle housing 30 containing the cradle 32 and tool holder 34. The tool holder 34 is mounted for rotation within the cradle 32 and about a generally horizontal axis which may be adjusted to a certain range or ranges of positions, as will be understood. The cradle housing and cradle structure are disclosed in more detail and claimed in the copending application Ser. No. 764,222, and, as disclosed therein, the cradle housing is mounted for horizontal slidable adjustable movement on the machine base frame 26 and in a direction perpendicular to the axis of cradle rotation. The tool holder, as will be understood, is designed to mount a rotary face 'mill cutter. The rotary tool holder, face mill cutter, and adjustablemeans in the cradle for tary tool holder may be conventional, as disclosed, for exam.- ple, in US. Pat. No. 2,667,818.

The single machine 28 shown in FIG. 2 also includes upstanding flanges or sidewalls 36, 38 suitably mounted on the frame 26c and extending upwardly therefrom in straddling relation to the cradle 32. As best seen in 'FIG. 1, these sidewalls 36 terminateat a point intermediate the heightof the cradle 32. A workhead assembly 40 is mounted between these sidewall members 36, 38 and includes arotatable work holder 42 mounted therein and designed to receive the. work to be cut so that the work is rotatable about a vertical til" generally vertical axis. The workhead assembly land the s'truc'ture for mounting the workhead assembly in the'machin'e willj be described in more detail hereinbelow. As will become ap parent, the workhead assembly 40' is designed to be reciprocated back and forth in a horizontal direction both toward and away from the cradle 32 and tool holder. The workhead assembly is also designed to be pivoted'or rotated througha limited angle and about a horizontal axis extending between the sidewall members 36, 38, and it will be adjustable in a vertical direction in connection with initial setup of the machine, as will become apparent. Additionally, the present invention contemplates use of means for securely clamping or holding the workhead assembly and work in a fi rm andsecure position during the cutting operations 'so as to resist vibrations or other undesirable motions that might otherwise be imparted between the work and tool. i

Thus, it will be seen the machine of FIG. 2 presents a structural orientation for the cradle housing, cradle, tool holder and workhead assembly designed to provide increased strength, support, and stability during cutting operations, so 'as to minimize vibrations, etc. It willltherefore be possible'to rotate the tool at a higher r.p.m'. $0 that the time for the cutting cycle for each. tooth may be reduced.

The same basic structural orientation just described, and shown in FIG. 2, will be seen to be included in each cutting station in the two double machines 20, 22. Additionally, the double machines are shown as including conveyor means 44a, 44b for feeding pinion gear blanks, or pinion gears which have been partially roughed, to the machine, and work loading and unloading, turretlike structures 46a, 46 b are also provided for automatically transferring the work from the conveyor means 44a, 44b to the first cutting station and then to the other cutting station of the machine associated therewith, and then finally back to the conveyor means, as is disclosed and claimed in copending application Ser. No. 764,219.

A novel control means is also provided for controlling the operation of the work loading and unloading structure 46, and is indicated schematically by reference numerals 48a, 48b, in FIGS. 3 and 4. This control means is disclosed and claimed in copending application, Ser. No. 764,220. A chamfering means indicated schematically by reference numeral 50 is shown in FIG. 4 as being associated with the conveyor means 44a adjacent the double roughing machine'22, and is disclosed and claimed in copending application, Ser. No. 764,216.

, THE DRIVING ARRANGEMENT It will be understood that in generation of bevel gears, such as spiral bevel or hypoidgearsQthere commonly are two basic elements, the cradle and the work spindle, both of these being located in a certain spaced relationship with one another and rotating in a predetermined timed relationship ontheir respective axes. Conventionally, the cradle carries a rotating,

multibladed face mill cutter (not shown) whose axis is in adrepresent the imaginary generating gear," as is understood, 1

and the rotating cutter blade edges represent a tooth of this imaginary generating gear. The work spindle carries the work being cut; the cradle carrying the cutter rotates about adjusting the position and angle of the face mill cutter and rothe cradle axis in timed relation to the rotation of the work spindle with the rotating cutter in engagement with the work. Thus the imaginary generating gear is said to roll with the work piece.

The roll proceeds sufficiently to complete the generation of one tooth slot (or in some cutting operations, one side of one previously roughed tooth slot), whereupon there is a withdrawal so that the cradle with its cutter and the work are relatively separated one from the other in the direction of the cradle axis. The rolling motion of both cradle and work spindle is reversed during which time an increment of motion is added to the work spindle such as to advance (index) the work relative to the cradle by one pitch. At the completion of the reversal of roll, called the return roll, relative cradle axial movement between cradle and work again occurs to bring the two into cutting position, whereupon a cycle is repeated to cut the following tooth. It will be understood that, if desired for certain cutting operations, a cutting action could be provided on the return roll, after which the cutter and work will be relatively withdrawn, and the work indexed for the next tooth cutting cycle.

THE GENERATING TRAIN The generating train of the machine, as will be understood, is the complete connection between the cradle and work spindle for controlling the relative generating rotation of these two members. The illustrative embodiment of the generating train shown in FIG. 16 will now be traced. A worm gear 52 is fixed rotationally to the cradle 32, and this gear is engaged by a worm 54 connected to a telescoping shaft 56 on which is mounted a change gear 58. This is the point in the train where there is introduced a set of four change gears, a selection of which governs the ratio of generating roll between the cradle and work. Continuing through this latter set of change gears 60, 62, 64 through shaft 66, there is a connection to a suitable index differential gearing 68. Except during the indexing interval, which will be referred to again hereinbelow, the index differential 68 can be regarded as a simple train of gearing with gear 70 meshing with gear 72 which is rigidly connected to gear 74 meshing with a gear therebelow rigidly connected to gear 76 which in turn meshes with gear 78, as shown. Gear 78 is rigidly connected to or integral with bevel gear 80, in turn meshing with bevel gear 82 connected to shaft 84.

Shaft 84 is keyed for rotation to another bevel gear 86 engaging with a mating gear 88 fastened to a shaft 90 which is connected for rotation to a pinion 92 of a hypoid pair. The meshing hypoid gear 94 is rigidly connected to the work spindle. As will be understood, the work spindle is connected for rotation in the workhead assembly 40. This completes the trace of the generating train, that is, the gearing which links and controls the relative rotational motion of cradle and work during the generating rolls. It will be understood that this generating train will be capable of being rotated in either direction, for the forward and return rolls.

THE DRIVE FOR THE GENERATING TRAIN As shown in FIG. 16 the drive for the generating train includes a reversible hydraulic motor 118, driving through shaft 120 and roll change gears 122, 124 and fixed gearing 126, 128, the latter gear being rigidly attached to shaft 66 in the generating train. A controllable displacement, hydraulic pump 132 is shown as being connected to the hydraulic motor for controlled and reversible driving actuation thereof in conventional manner. The pump 132, in turn, is driven by a motor 134 which may be a constant speed electric motor. The electric motor 134, hydraulic pump 132, and hydraulic motor 118 and the various driving connections therefor may all be of conventional design.

OTHER STRUCTURES RELATED TO THE GENERATING TRAIN It will be understood that conventional indexing means 96 will be provided for indexing the work, at the end of each tooth cutting cycle. Suitable teachings for the construction of the indexing mechanism may be found in US. Pat. No. 3,229,552.

The present development also contemplates a control system 136 including a servomechanism designed to control the operation of the power source for the generating train through a differential connection 166, 168 as disclosed and claimed in the copending application Ser. No. 764,213.

A separate power source 177 is provided for the cutter, and shown as being connected thereto through pulleys l'79, l8l, belt 183 and gearing 185, as best seen in FIG. 16.

A helical motion mechanism 186 and a ratio control mechanism 188 are shown in FIG. 16 as being operatively connected to the cradle 32 and power source 118, respectively, for effecting desired cradle movements during cutting, as disclosed in copending applications Ser. Nos. 764,222 and 764,214.

It will be understood that the drive diagram shown in FIG. 16 for a single cutting station may be duplicated in a second cutting station of a double machine, with a separate servomechanism, corresponding to servomechanism 136, being provided therefor and operatively drivingly connected to the shaft 212 of the servomechanism 136, as disclosed in the copending application Ser. No. 764,213.

The present development further contemplates provision of novel work loading and unloading means 46, in combination with workhead assemblies 40 and conveyor means 44, with a control system 48 therefor operative to control the movements of the conveyor, work loading-unloading turret, and workhead assemblies so as to provide automatic feeding of the gears or work from the conveyor to the workhead assembly, to be automatically mounted therein for a cutting cycle and thereafter unloaded for movement to the opposite adjacent cutting station for a subsequent cutting operation at that station, and then to be redeposited back on the conveyor 44, as disclosed and claimed in the copending applications Ser. Nos. 764,219 and 764,220.

It will be observed that this feature, just discussed, of the present development provides for a more automated operation of the double machines, and in conjunction with the higher tool cutting speeds and reduced times for cutting, will advantageously contribute to an overall substantial increase in the production rate, as indicated in the copending application Ser. No. 764,212.

WORKHEAD ASSEMBLY An illustrative embodiment of the workhead assembly 40 of the invention will now be described in more detail, and in this connection, reference will be made to the mounting of the workhead assembly in a left side version of a machine illustrative of the present development, such as is shown in FIGS. 2 and 5. However, it will be understood the present development contemplates that a double rougher and a double finisher, such as shown in FIGS. 3 and 4, will each be provided with two such workhead assemblies wherein the right side version will be substantially a mirror image of the left side version to be described in detail herein. Thus, it will be understood that corresponding reference numerals for the various parts of the workhead assemblies shown in FIGS. 3 and 4 will indicate corresponding structures. Likewise, the various controlled movements of the left side version of the workhead assembly that will be described herein will also be provided by the workhead assembly of the right side version of a double machine, for coordinated work loading, unloading, and cutting operations, as disclosed in copending application Ser. No. 764,212.

Referring now to FIGS. 2 and 5-8, the illustrative embodiment of the workhead assembly will be seen to include three basic components, a workhead 240, a swinging base 250, and a sliding base 252, connected together in that order, as best seen in FIGS. 2 and 5. As indicated above, the workhead assembly 40 is supported by the sidewalls 36, 38 for horizontally reciprocable sliding movement back and forth toward and away from the cradle 32, so as to define an operative, cutting position adjacent the cradle, and a work loading and unloading position at a point removed from the cradle, and disposed below the work gripping means 254 on the arms of the turret 46 (as shown in FIGS. 3 and 4).

The workhead 240 and swinging base 250 are connected to the sliding base 252 at one end and the sidewall means 36 at the other end so as to be swingable or pivotable about a generally horizontal pivotal axis extending in a direction perpendicular to the sidewalls 36, 38, as will be described in more detail hereinbelow. This pivoting movement of the workhead and swinging base will be effected, in the illustrative embodiment, by means of a fluid pressure actuated means 255 disposed above the sidewall means 38 and connected to the sliding base 252 and swinging base 250, as will be described in more detail hereinbelow. The purpose of these pivoting movements of the workhead is to enable desired positioning and adjustment of the axis of the work in the work holder 42 depending upon the requirements of the particular cutting operation and the teeth to be cut. Thus the work holder may be moved between a work loading and unloading position wherein the work holder is arranged to receive the work with its axis vertical, and a cutting position where the axis of the work may be inclined somewhat from the vertical.

As best seen in FIGS. 2, 5 and 7, the left-hand end of the workhead 40, as viewed in those FIGS. is connected to structure arranged for slidablemovement relative to the upstanding flange or sidewall 36 by means of a track member 256 suitably fastened to the sidewall 36. Roller means 258 are arranged in track member 256 and are connected to the workhead 240 through an outboard rail or support member 260. The track member 256 is shown in FIG. as being generally C-shape in vertical section and includes two rails 262, 264 secured therein, and engageable by the roller means 258.

Suitable means are provided for releasably clamping the roller means in the track member so as to provide a secure and more stable gripping action at this end of the workhead assembly whereby vibrations, etc. during cutting operations will be resisted. FIG. 10 shows an exemplary arrangement of such a clamping means wherein a vertical piston 266 is slidably arranged in a pressure chamber 268 in the sidewall 36 and urged by spring 270 downwardly. This piston is disposed below the rail member 264 within the track member 256, and a screw 272 is shown connected to this rail 264, and extending downwardly therefrom. As shown, there is some clearance between the head portion 274 of the screw and the adjacent surfaces of the track member 256, and the head portion is disposed directly above the piston 266.

A fluid passageway 276 communicates with the lower end of the chamber 268, and when a clamping action is desired, fluid under pressure will be introduced through this passageway into the chamber to urge the piston upwardly (against the action of spring 270) and against the head 274 of the screw 272'so that the rail 264 will be pressed vertically upwardly against an outer shoe 278, slidable on the track 264, as will be evident. A plurality of such clamping means, including pistons 266 and screws 272 may be provided, spaced along the length of the track member 258 and sidewall 36 as will be evident.

The roll means 258 includes the outer shoe 278 on rail 264 and an inner roller 280 journaled on a pin 281 coaxial therewith. Roller 280 is arranged on the shorter rail 262, as best seen in FIG. 10. The pin 281 is suitably fastened to the outboard support rail 260, at the upper end thereof, and a generally horseshoe-shaped guard 282 may be disposed around the larger roller 280, functioning as a shield to prevent foreign matter, such as cuttings or the like, from getting wedged between the roller and the rail.

The outboard vertical support rail 260 includes a vertically extending T-slot 284 and an adjacent and parallel groove 286, as best seen in FIGS. 7 and 9. The left-hand end of the workhead 240, as viewed in FIGS. 5 and 7, is shown as being connected to the vertical support rail by means of an elongated, rectangular slide 288 slidably disposed in the slot284 and threadedly receiving a bolt 290 fastened in a flange 292 of the workhead, as best seen in FIGS. 9 and 10.- This connection provides for vertical adjusting movement of the workhead relative to the swinging base, as will become'apparent as the description proceeds. v

The flange 292 of the workhead also is shown as including a roller 294 disposed within the groove 286 of the outboard 'support rail 260 and spring urged into engagement therewith as I by compression spring 294 arrange'd ijn a bracket 296 in which the roller 294 is journaled. l I

A fastening plate 298 is shown in FlG. 9 as being fixedly connected to the workhead 240 andslidably connected to-the vertical support rail 260 to provide additional support for the workhead while permitting the latter to be moved vertically relative to the support rail, as best seen in FIG. 9. j 1

At the other end of the workhead 240 (the right end,as viewed in FIGS. 2 and 5), it is connected to the swingable base 250 and the latter is connected to the sliding base 252which in turn is mounted for sliding movement relative to the ad jacent upstanding flange or sidewall 38. The workhead 240 is shown as being connected to the swinging base 250 for adjustable vertical positioning thereon by means of three horizontal, elongated bolts 300 extending through lugs 302 and flanges 303 in the workhead 240 and threadedly connected to nonrotatable heads or nuts slidably disposed in vertical T-slots or slideways 306 in the swinging base 250, as shown in FIG. 8. The swinging base is shown as including another vertically extending groove 308 disposed between the slideways 306, and the workhead 240 is shown in FIG. 17 as .being provided with a vertically extending projection or tonvertical adjusting movements of the workhead relative to the swinging base, suitable means are provided'and, in the illustrative embodiment thereof, such means includes a vertical rod member 316 extending through the workhead 240 and threaded at its lower end in an internally threaded nut member 318 suitably fixed to the bottom of the swinging base, as "indicated in FIG. 8. The upper end of the rod member 316' is shown as being provided with a socket 320 designed to be engaged by a suitable wrench or tool, and an adjusting screw dial 322 is shown connected to the upper end of the rod by a setscrew and it cooperates with a dial member 324 disposed therebelow and fixed to the workhead 240 in stationary position, as by the fastening screw 326. The rod member 316 is shown as including a shoulder 328 in the upper end thereof journaled in a recess 330 in the workhead and suitable bearings 332 are provided between this collar and the stationary dial 324.

Thus, when it is desired to adjust thevertical position of the workhead relative to the swinging base 250, the bolts 300 will be loosened so as to release the clamping effect of their corresponding nut members 304 in the slots 306 of the swinging base, and the rod member 316 will be rotated, as desired, as'by use of a suitable tool engaging the socket 320. The amount of adjustment will be indicated or read off the scale 312 and dial 322, the former being for coarse readings, and the latter for fine reading. It will also be noted that in order to permit this vertical adjusting movement of the workhead 240, it will be necessary to release, the clamping action of the bolt 290 and elongated slide 288 connecting the workhead to the outboard support rail 260, as shown in FIG. 9, In this connection, it" is also contemplated that suitable means be utilized to provide vertical support at this end of the workhead when the bolt 290 is loosened. Such means is shown as including a piston member 334 supported at is lower end on a flange 336 fixed to the outboard support rail 260, and extending into a chamber 338 in the flange of the workhead and fluid under pressure will be introduced into this chamber above the pistonto provide vertical support for the workhead. This pressure will operate to provide a fluid supporting column, such as of oil, and the height of this fluid column willvary somewhat during the adjusting movements, as will be understood.

The workhead 240 is shown in FIG. as mounting an uncut gear blank W. The means for mounting the work W in the work holder may be of suitable conventional construction, as indicated, for example in U.S. Pat. No. 2,667,818, and which will permit automatic chucking and dechucking, as will be understood. Likewise, the structure for rotating the work spindle during cutting operations, as during rolling and indexing, may also be of suitable, conventional design so as to permit the various movements of the workhead during vertical adjustment, loading and unloading. For this purpose, the teachings of U.S. Pat. No. 2,667,818, may be utilized, as will be evident. The illustrative embodiment of the present invention includes means for pivotally connecting the swinging base 250 to the sliding base 252, as shown, for example, in FIGS. 5, 6, 8, 11 and 12. As best seen in FIG. 6, the sliding base 252 includes a spindle or trunnion 340 extending horizontally therefrom, and a circular slot 342, T-shape in vertical cross section, and whose center of curvature is the axis of the trunnion340. The swinging base 250 is shown in FIG. 8 ashaving'a top member 344 attached thereto, as by bolts 346 and including a boss 348 having a bearing 350 journaled to the trunnion 340. The lower end of the swinging base 250 is shown in FIG." 15 as being releasably clamped to the slidable base 252"by means of a clamping means 352 includingmember 354' projecting into the T-slot 342 in the sliding base at one end, and at the other end thereof being disposed in a recess 356 in theswinging basefiSpring washers 358 are shown as being disposed in the recess 356 in engagement with the annular flange 360 of member 354 to continuously urge it to the left, as'viewed in FIG. 15, for the purpose of holding the strap 362 in a tightly clamped position in the T-slot'342. Strap 362 threadedly receives the end of member 354, as indicated. 8

A piston cap'member 364 is shown as enclosing the annular flange of the member 354 and the spring washers 358, and a chamber 366 is provided between the piston head and a closure member 368 whereby fluid under pressure may be introduced into this chamber to urge the piston 364 and member 354 to the right, as viewed in FIG.'15, against the action of the spring washers 358, to release the clamp, whereby the swinging base may be pivoted (with the workhead attached thereto) about the axis of trunnion 340 by structure to be described inmore detail here'inbelow. It will be noted that the axis of trunnion 340 on the'sliding base 252 coincides with the axis of the rollers 278,280 at the other end of the workhead assembly so that when the swinging base and workhead are pivoted, the pivotal axis therefor will be defined by a horizontal axis extending between the upstanding flanges or sidewalls 36, 38 and perpendicular thereto, and coincident with the axis of the rollers 278, 280 and trunnion 340.

In the illustrative embodiment of the invention, pressure actuated means are provided for pivoting the swinging base 250 and workhead 240 about the axis of the trunnion 340 and rollers 278, 280. This means is shown as including a cylinder housing 370 having a horizontal trunnion 372 suitably connected thereto, as shown in FIG. 12, and suitably journaled in a bracket 374 fixed to the top of the sliding base 252. The housing 370 will therefore be swingable or rotatable about the axis of the trunnion 372, as will be evident. The housing 370 is shown as including an upper 376 and lower 378 closure cap suitably fastened thereto in fluidtight manner, and a piston head 380 is slidably disposed in the chamber within the cylinder 370, as best seen in FIGS. 11 and 12, and mounted on a rod 382 extending through the upper and lower closure caps for reciprocation therein.

The lower end of the piston rod 382 is shown as being threadedly connected to a bracket 384 mounted between upstanding lugs 386 on the swinging base 250. The bracket 384' carries a pin 388 fixed thereto and suitably journaled in the upstanding lugs 386, as shown.

' Thus, when the piston 380 is reciprocated vertically in the chamber 390 it will move the rod 382 up and down so as to swing the pin 388 and swinging base 250 about the axis of the trunnion 340 on the sliding base, as will be evident, and the housing 370 will rotate about the axis of its trunnion 372, as

required, to effect the pivoting of the swinging base. The pin 388 is shown in FIG. 12 as being held in the bracket 384 by screw 385. r I

Suitable passageways and valves are provided, as will be described in more detail hereinbelow, for introduction of fluid under pressure into the chamber 390, either above or below the piston head 380, to effect the pivoting of the swinging base. The purpose of so pivoting the swinging base is to move the workhead 240 between a cutting position, and a work loading and unloading position. In the illustrative embodiment of the invention, the load position preferably is such that it places the axis of the work holder 42, mounted in the workhead 240, in a vertical position, such as shown in FIG. 8. The workhead may be pivoted to a cutting position within a certain range of positions, on either side of the vertical. 1

' A vemier scale 392 is provided on the sliding base 252 and it may be arranged so that a reading of 0 indicates true verti cal position of the axis of the work in the workhead. An illustrative range of cutting positions could be approximately 348 to 12, or approximately 12 to either side of the vertical position. The precise control of the loading, unloading and cutting positions is shown as being made by means of replaceable shims 394, 396 suitably arranged onthe lower and upper ends of the piston rod 382, as shown in FIG. 11. These shims are precision made in desired thicknesses to regulate the two extreme positions of the actuating piston 380, and it will be understood that they are replaceable by shims of different thicknesses than that shown to provide different stop positions for the travel of piston rod 382. The actual terminal positions of the vertical travel of piston rod 382 are established by the abutment of horseshoe collars 398, 400 against positive stops '402, 404-provided on the lower and upper housing closure caps 378, 376, respectively.

In the illustrative embodiment, means are provided for opening the cylinder upper 390a and lower 390b chambers automatically to pressure and exhaust and for dashpot action. This means is shown as including lines 406, 408, 410, the latter two lines opening into recesses 412, 414 on a valve spool 416 vertically slidable within a bore in the housing 370, as shown. There are also provided lines 418, 420, 422 opening into recesses 424, 426 in another valve spool 428 also vertically slidable in-a bore in the housing 370, as shown. Spool 416 is continuously urged by spring 430 to its lowermost position, and will have a travel as indicated in FIG. 11, while spool 428 is continuously urged to its uppermost position by compression spring 432, and preferably will have the same amount of p travel as spool 416. These spools 416, 428 preferably are of identical construction. I

It will be noted that for convenience of illustration the connections between lines 406, 410 and 418, 422 are shown in phantom in FIG. 11. There are connecting lines 432, 434 between the bores "for the spools 416, 428 respectively, and the large cylinder chambers 390a, 39% respectively. In the position shown, line 408 may be put on pressure so that pressurized fluid, such as oil, may be freely transmitted into chamber 390a through line 410, spool recess 414 and the port leading into the line 432.

In the movement of the piston 380 downward, which preceded its establishment in the position shown, there was also a downward movement of the spool 416 caused by the spring 430, as will be evident. At the start of this downward spool travel, line 410 had been blocked by spool land 436, but pressure was still admitted to chamber 390a through lines 406, 408 spool recess 412, hole 438, poppet valve cylinder 440 and through the open poppet valve 442, and then through recess 414 and line 432 into chamber 390a. The poppet valve 442 will be opened against the compression spring 444 by the pressure fluid. It will be noted that the stem 446 of the plug 448 will limit the poppet valve open position. Thus, for forcing the 

1. A gear cutting machine comprising a frame having upstanding spaced and parallel side flanges defining a space therebetween, slide means slidably mounted to and movable along one of said flanges, a workhead disposed in the space between the flanges and pivoted to the slide means for swinging movement about a horizontal axis perpendicular to the direction of slide motion, a work spindle journaled in said workhead for rotation about and axis perpendicular to said first-named axis, and a tool-support column on said frame.
 2. A machine according to claim 1 having clamping means for securing the flanges to the column, and the workhead to the slide means.
 3. A machine according to claim 2 and further including a hydraulic actuator for moving said slide means to and away from a stop on said one of the flanges.
 4. A machine according to claim 1 having a tool-support cradle rotatable in the column on an axis parallel to the slides.
 5. A gear cutting machine comprising a frame, a cradle housing mounted on said frame, spaced and parallel sidewalls arranged on said frame at either side of said cradle housing and defining a space therebetween a cradle in said housing and disposed intermediate said sidewalls, a workhead assembly, means operatively suspending said workhead assembly from said sidewalls for slidable movement of said workhead assembly toward and away from said cradle housing, said workhead assembly being disposed in the space between said sidewalls, said workhead assembly including a work holder and means for pivoting said work holder between a cutting position and a work loading and unloading position.
 6. The structure defined in claim 5 and further including means for rectilinear adjustment of the position of said work holder in said workhead assembly.
 7. The structure defined in claim 5 wherein said pivoting means includes pressure actuated means and further including stopping means for limiting the pivoting movement of said work holder in either direction.
 8. The structure defined in claim 7 wherein said stopping means includes precision-made parts of predetermined thickness replaceably mounted in said stopping means.
 9. The structure defined in claim 5 wherein said workhead assembly includes a workhead, a swinging base, and a sliding base, means releasably connecting said workhead to said swinging base providing for rectilinear adjusting movements of the workhead relative to the swinging base.
 10. The structure defined in claim 9 and further including means pivotally connecting said swinging base to said sliding base, and said means operatively suspending said workhead assembly from said siDewalls including: means engaging said sliding base to one of said sidewalls and means operatively engaging said workhead to the other of said sidewalls.
 11. The structure defined in claim 10 and further including means for reciprocating said workhead assembly toward and away from said cradle housing and including stopping means for limiting this movement of the workhead in both directions.
 12. The structure defined in claim 11 wherein said reciprocating means includes pressure actuated means, and wherein said stopping means includes a precision-made part of predetermined thickness replaceably mounted in said stopping means, and wherein said stopping means further includes an adjustable stopping surface and means operatively connected to said surface for precision adjustment of its position.
 13. In a gear cutting machine having a base and a tool support column mounted thereon, the improvement which comprises a workhead assembly including a workhead disposed to receive a work piece so that the axis of rotation of the work piece will be generally vertical; parallel, spaced sidewalls; and means for mounting said workhead assembly to said sidewalls for reciprocation toward and away from said tool-supporting column, and said workhead assembly being supported by and between said sidewalls.
 14. The structure defined in claim 13 and further including clamping means for providing for a firm connection of one end of said workhead to one of said sidewalls, means for pivoting said workhead about a horizontal axis extending between said sidewalls.
 15. The structure defined in claim 14 wherein said pivoting means includes pressure actuated means including a housing mounted for rotation about a horizontal axis parallel to said pivotal axis for said workhead, and a piston reciprocally mounted in said housing, said housing and said piston being operably connected to different parts of said workhead assembly.
 16. The structure defined in claim 15 wherein said workhead assembly includes a swinging base and a sliding base, said workhead being connected to said swinging base, said swinging base being pivotally connected to said sliding base, said housing being journaled to said sliding base and said piston being operably connected to said swinging base.
 17. In a gear cutting machine having a base and a tool-support column mounted at either end thereof, the improvement which comprises the following structure adjacent each tool-support column a workhead assembly including a workhead disposed to receive a work piece so that the axis of rotation of the work piece will be generally vertical; parallel, spaced sidewalls; and means for mounting said workhead assembly to said sidewalls for reciprocation toward and away from the adjacent tool-support column, and said workhead assembly being supported by and between said sidewalls.
 18. A workhead assembly to be used in a gear generating machine and including: a workhead including a work holder; a swinging base; a sliding base; first means for connecting the workhead to the swinging base; second means for pivotally connecting the swinging base to the sliding base so as to pivot about an axis extending in a direction perpendicular to the axis of the work holder, said first means providing for rectilinear adjustment of said workhead relative to said swinging base, said second means including releasable clamping means connecting said swinging base to said slidable base; pressure actuated means for pivoting the swinging base and the workhead relative to said sliding base, said last-named means including a housing journaled on to said sliding base and a piston reciprocably arranged in said housing and operatively connected to said swinging base.
 19. The structure defined in claim 18 wherein the pivotal axis for said swinging base and the pivotal axis for said housing are spaced apart and parallel. 